This invention relates to a hose clamp used for binding in place a rubber hose, for example.
The hose clamps of this type which have come into use to date will be explained. First, the hose clamp disclosed in U.S. Pat. No. 3,008,206 is cited. In this hose clamp, a clamp body comprising an annular clamping ring part and a pair of grip parts is formed of a resilient wire of a circular cross section. This is the most primitive of all of the hose clamps. It has a problem in respect that when it binds a given rubber hose, it exerts a concentrated stress upon the bound portion of the rubber hose and accelerates the aging of the rubber hose.
As a solution for the problem, the hose clamp disclosed in U.S. Pat. No. 3,038,230 has been proposed. This hose clamp comprises a clamp body formed of a resilient flat sheet material and screw members adapted to link the opposite terminal parts of the clamp body, so that the binding force of the clamp body may be adjusted with the amount of helical engagement of the screw members. It is, therefore, capable of repressing otherwise possible concentration of stress upon the bound portion of a rubber hose. Conversely, however, it entails a disadvantage that the opposite terminal parts of the clamp body are required to allow for extra spaces for accommodation of the screw parts and that the assembly of the hose clamp requires an unduly large number of steps.
Thus, the hose clamps disclosed in U.S. Pat. No. 3,082,498, No. 3,106,757 and No. 3,295,176 have been proposed. These hose clamps invariably comprise an annular clamp body formed of a resilient flat sheet material and adapted to have part of the circular wall thereof projected outwardly in such a manner that when the opposite sides of the projected wall are squeezed toward each other with a jig, the clamp body is shrunk radially and allowed to exert a binding force upon the rubber hose. Therefore, they entail a disadvantage that since the amount of this radial shrinkage of the clamp body has its limit, the rubber hoses capable of being bound by these hose clamps automatically have their dimensional limits.
In recent years, therefore, the hose clamp disclosed in U.S. Pat. No. 4,305,179 has come to find increasing utility. In this hose clamp, a clamp body formed of a resilient flat sheet material cut in a prescribed shape comprises an annular clamping ring part and a pair of grip parts raised from the opposite terminal parts of the ring part and extended in mutually opposite directions. Owing to this construction, this hose clamp is capable of repressing the otherwise possible concentration of stress during the course of clamping to the fullest possible extent and allowing for appreciable freedom in the variation of the diameter of the clamping ring part.
In this hose clamp, however, during the course of the work of inserting a rubber hose inside the clamping ring part, the clamping ring part must be expanded radially by squeezing the pair of grip parts toward each other with a tool. The field workers have expressed a desire for this hose clamp to be improved so as to eliminate the inconvenience encountered in this inevitable work of imparting a radial expansion to the ring part.
As an answer to this demand, the hose clamp disclosed in Japanese Utility Model Publication No. SHO 52-14511 has been proposed.
In this hose clamp, a clamp body formed of a resilient flat sheet material cut in a prescribed shape comprises an annular clamping ring part for clamping a rubber hose and a pair of grip parts raised from the opposite terminal parts of the ring part and extended in mutually opposite directions. The hose clamp is separately provided with a holder formed in a U-shaped cross section and adapted to retain the pair of grip parts in a state approximated to each other in spite of their resilient force.
When this hose clamp is put to actual use, the clamping ring part is radially expanded in advance by inserting the holder around the pair of grip parts in a state urged toward each other, thereby temporarily retaining the grip parts in the state of mutual approximation. Then, the rubber hose is inserted into the radially expanded clamping ring part and fitted on the terminal part of a connection pipe. Now, the holder is removed from the pair of grip parts to relieve the pair of grip parts of their mutual approximation and allow the clamping ring part to shrink radially automatically by the resilient force of its own, with the result that the rubber hose is bound fast on the pipe infallibly.
This hose clamp, therefore, enjoys an advantage of extremely simplifying the work of insertion of the rubber hose inside the clamping ring part because the radial expansion of the clamping ring part due to the use of the holder facilitates impartation of the state of radial expansion to the clamping ring part. When the rubber hose given to be clamped happens to have a relatively small diameter, however, it is often observed that the clamp body fitted in place in advance is compelled to move unexpectedly on the periphery of the rubber hose during the insertion of the rubber hose of small diameter around the terminal part of the connection pipe.
Once this phenomenon takes place, the field worker is compelled, after having inserted the rubber hose around the terminal part of the pipe, to reset the unexpectedly displaced clamp body to the prescribed clamping point of the rubber hose. The hose clamp, therefore, entails a disadvantage that this work of resetting will greatly annoy the field worker.